There is known, as an electrographic printer, a printer provided with a photosensitive member and a developing apparatus that supplies the photosensitive member with toner.
One such a developing apparatus mounted to a printer include a developing roller that carries the toner, a supply roller that supplies the developing roller with the toner, and a layer-thickness regulating blade that regulates thickness of the toner on the developing roller to a predetermined value.
In this developing apparatus, the layer-thickness regulating blade includes a support portion made of iron or stainless steel, a plate spring attached to a distal end of the support portion, and a semicylindrical pressing member formed of silicone rubber and provided on the plate spring. The layer-thickness regulating blade is brought into contact with the developing roller at a curved part of the pressing member.
Further, in this developing apparatus, the side end of a side seal slides the side end surface of the supply roller.